1var baseFlatten = require('./_baseFlatten'),
2    baseOrderBy = require('./_baseOrderBy'),
3    baseRest = require('./_baseRest'),
4    isIterateeCall = require('./_isIterateeCall');
5
6/**
7 * Creates an array of elements, sorted in ascending order by the results of
8 * running each element in a collection thru each iteratee. This method
9 * performs a stable sort, that is, it preserves the original sort order of
10 * equal elements. The iteratees are invoked with one argument: (value).
11 *
12 * @static
13 * @memberOf _
14 * @since 0.1.0
15 * @category Collection
16 * @param {Array|Object} collection The collection to iterate over.
17 * @param {...(Function|Function[])} [iteratees=[_.identity]]
18 *  The iteratees to sort by.
19 * @returns {Array} Returns the new sorted array.
20 * @example
21 *
22 * var users = [
23 *   { 'user': 'fred',   'age': 48 },
24 *   { 'user': 'barney', 'age': 36 },
25 *   { 'user': 'fred',   'age': 30 },
26 *   { 'user': 'barney', 'age': 34 }
27 * ];
28 *
29 * _.sortBy(users, [function(o) { return o.user; }]);
30 * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 30]]
31 *
32 * _.sortBy(users, ['user', 'age']);
33 * // => objects for [['barney', 34], ['barney', 36], ['fred', 30], ['fred', 48]]
34 */
35var sortBy = baseRest(function(collection, iteratees) {
36  if (collection == null) {
37    return [];
38  }
39  var length = iteratees.length;
40  if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {
41    iteratees = [];
42  } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {
43    iteratees = [iteratees[0]];
44  }
45  return baseOrderBy(collection, baseFlatten(iteratees, 1), []);
46});
47
48module.exports = sortBy;
49